flyway vs migration route

flyway and migration route both are nouns.

Word	Noun	Adjective	Verb	Adverb
flyway	Yes	No	No	No
migration route	Yes	No	No	No

As nouns, flyway and migration route are synonyms defined as:

flyway and migration route: the geographic route along which birds customarily migrate

flyway (noun)	migration route (noun)
the geographic route along which birds customarily migrate	the geographic route along which birds customarily migrate